French Drain Case Study: Managing Neighbour Runoff in Shellharbour

Addressing Water Ingress in Shellharbour

A homeowner in Shellharbour faced a significant and escalating issue with water ingress. Water from two adjacent properties, both situated at a higher elevation than the client's land, was flowing into the yard and infiltrating beneath the slab. This intrusion resulted in damaged flooring, rising damp, and the emergence of mould within the residence, putting recent renovations in jeopardy.

Identifying the Source of Water Intrusion

The problem stemmed from both surface runoff and subsurface water flowing downhill from the back and side yards of neighbouring properties. Without sufficient drainage to intercept this water, it had no option but to migrate beneath the house.

Implementing a Drainage Solution

CS Plumbing devised and installed a gravity-fed French drain system designed to intercept and redirect water before it could reach the home's foundation.

The project involved several key elements:

A French drain system to capture both surface and subsurface water from the boundaries of the neighbouring properties, directing it through gravity to a concrete pit.
A 100mm PVC pipe extending from the pit to the kerb, featuring neatly drilled holes in the kerb for effective discharge.
Three new, larger-diameter Colorbond metal downpipes replacing the original smaller versions, connected to new 100mm PVC pipework that leads to the kerb.
A retaining wall system constructed along the boundary using concrete sleepers and galvanised steel posts, with auger holes drilled using an excavator to create an engineered barrier that holds back the adjacent yard.
On-site soil removal carried out with a dumper for efficient site management.

Achieving Effective Water Management

The newly implemented system now effectively intercepts surface and subsurface water at the boundary, ensuring it is directed away from the property. The homeowner has gained a long-lasting, low-maintenance solution that safeguards their foundation, flooring, and investment in renovations.